cummean()
oops, intseq() edge case

You can't request more indecies than exist in the first place
HAHAH I forgot to actually write the call that made intseq operate.
omg apparently i broke NIW when i factored it earlier; durrrrrp. I didn't run the rests! I shoulda run the tests.
Start to use apply() magic to simplify the moment code
dNIW API change: support vectorized probability densities (like every other d* function in R)
[UNTESTED] Use more apply() magic and the previous to plot first and second moments generically.
use the new moment code
remove the moment code which is now ported
code cleanup + remove the annoying space in the moment titles
coherence: tweak the names of the test functions and reenliven the NIW.moment functions into test.correctness instead of test.correctness.main